Ferrite Resonators for Microwave Devices

The article presents the results of a comprehensive theoretical and experimental study of ferromagnetic resonance and microwave magnetoelectric effect in multilayer ferrite-piezoelectric structures containing single-crystal iron-yttrium garnet of cut (111) in combination with piezoelectric materials. Mathematical modeling of physical processes occurring in ferrite was performed, which made it possible to reveal weak magnetic cubic anisotropy, which must be taken into account when developing electrically tunable microwave devices. It was experimentally established that the homogeneity of the internal magnetic field and the quality factor of the resonators depend significantly on the geometry of the ferrite component and the quality of its surface. It is shown that for the realization of devices with the required electrical tuning it is necessary to minimize the thickness of the ferrite component and to use piezoelectrics, which are characterized by the maximum difference of piezoelectric coefficients d₃₁ and d₃₂. The obtained results open up prospects for the optimization of existing and creation of new magnetoelectric microwave devices with electrical and magnetic tuning of frequency and phase characteristics.